1. Field of the Invention
The present invention relates to a semiconductor light-emitting apparatus and a method of fabricating the same, and more specifically, to a semiconductor light-emitting apparatus in which a semiconductor light-emitting device is mounted on a supporting board by bonding members.
2. Description of the Related Art
A surface-mounted light-emitting apparatus using a semiconductor light-emitting device chip (hereinafter referred to as “light-emitting device”) such as a light-emitting diode (LED) or a laser diode is known in the art. As such an apparatus, there is known an apparatus in which a light-emitting device having p- and n-electrodes on the same side is flip chip-mounted on an insulative supporting board on which a wiring pattern including positive and negative electrodes is formed, in order to enhance the light extraction efficiency. In this case, a solder paste, such as an AuSn solder paste, is applied on a predetermined area of the supporting board on which the positive and negative electrodes are formed, a light-emitting device provided with an Au bump is flip chip-mounted on the supporting board, and then, the solder is reflowed. Peripheral portions of the light-emitting device and the bump are sealed with a light-transmitting sealing resin.
The light-emitting apparatus of the above structure exhibits strong bonding strength and has a superior reliability, since the light-emitting device and the supporting board is bonded with the Au bump, which has a certain level of height. However, because of the height of the bump, the sealing resin intervenes between the light-emitting device and the supporting board in a large amount. When the intervening resin is subject to thermal stress, the stress progresses from the wiring pattern to the light-emitting device. When the amount of the intervening resin is large, or when the light-emitting apparatus of the above structure is used in an environment involving sever change in temperatures, this stress becomes so strong as to adversely affect the adhesion between the light-emitting device and the sealing resin or the bonding between the light-emitting device and the wiring pattern, resulting in lowering of reliability by the absorption of moisture and in poor bonding of the light-emitting device, leading to non-lighting of the light-emitting device.
On the other hand, a light-emitting apparatus has been proposed in the art, in which a light-emitting device is mounted on a supporting board by means of a bonding member other than an Au bump. However, when the distance between the light-emitting device and the supporting board becomes small, it is necessary to take measures to prevent short-circuiting between the p- and n-electrodes on the light-emitting device and between the positive and negative electrodes on the supporting board.
Jpn. Pat. Appln. KOKAI Publication No. 2005-38892 discloses, for the purpose of preventing short-circuiting between p- and n-electrodes on a light-emitting device and between p-type and n-type compound semiconductor layers, forming a recess or groove in a boundary region between the positive and negative electrodes on the supporting board. The solder, heated and compressed between the light-emitting device and the supporting board and tending to run off from between the light-emitting device and the supporting board, flows into the recess, whereby the short-circuiting between the positive and negative electrodes by the solder is prevented. However, when the distance between the p- and n-electrodes is made small to increase output power or when the n-electrode on the light-emitting device is made smaller, volume of the recess sufficient to prevent the short-circuiting can not be acquired, leading to the short-circuiting between the two electrodes on the light-emitting device by the solder.
Further, Jpn. Pat. Appln. KOKAI Publication No. 2008-4948 discloses, in FIG. 1, that in a face down-mounted LED device, the distance between positive and negative electrodes on a submount is broader than the distance between p- and n-electrodes on a light-emitting device. However, if the p-electrode on the light-emitting device is arranged near the positive electrode on the submount, the p-electrode on the light-emitting device is short-circuited with the negative electrode on the submount when the bonding is effected by means of an electrically conductive material.